Plate-clamp



Patented June 29, 1920.

2 SHEETS-SHEET I.

TTKS y 2 SHEETS--SHEET 2.

Patented June 29, 1920.

J. WHITE.

PLATE CLAMP. APPLlcArloN man sPT.24, 191'9.

, Q NQQ adapted.

4'to carry out my present invention.

UNITED srn'frlazs PATENT OFFICE.

fJosEPH WHITE, oF PISCATAWAY TOWNSHIP, NEW JERSEY, AssIGNoa To yHALL PRINTING PRESS COMPANY, OF DUNELLENQ'NEW JERSEY,YA CORPORATION 0F NEW JERSEY.

PLATE-CLAMP.

Speci'cation of Letters Patent. Patented June 29, .1920.

. i Application led September 24, 1919. Serial No. 325,944. v

T0 all whom t may concern.' A

Be it known Vthat I, JOSEPH WHITE, a citizen of the United States, residing at. Piscataway township, State of NewJersey, (Post-oilice address, Boundbrook, New Jersey,) have invented certain new and .useful Improvements in Plate-Clamps; and I do declare the following to be a full, true,vand exact description of said invention, such' as will enable others skilled in the. art to whieh it appertains to make and use the same. l

This invention relates to clamps for holding flexible plates or sheets on a supporting bed, and particularly. clamps Vfor positioning and holding flexible planographic printing plates onl the beds of vprinting presses. v v

In order to adjust such a plate in a printing press so as to bring it into proper printing relation, vparticularly with previously printed iorms, it is desirable not only to be able to adjust the sheet as a whole both lengthwise and crosswise of the bed, but it is also desirable at times to stretch the sheet laterally. It is to accomplish this purpose that my present invention is particularly VW'ith these and other objects in view, my

4invention Vconsists of' certain novel features of construction, combination and arrangement of parts,"as Vwill be more fully described and pointed out in the appendedk claims. j y

VIn the drawings, Figure Vv1 represents ka plan view Vvof a printing press cylinder, which I have adoptedfor purposes of illustration, in which an illustrativel form of clamp is shown holding the printing plate in position; Fig. V'2'is a plan, Fig. 3 a front elevation and Fig. Ll' a side elevation, partly, in section, of an enlarged view of oneof the clamps in my preferred form, as arranged The corresponding parts are referredto, both in the specification and in theu drawin s, by similarreference characters.

y present invention is` illustrated in connection with a printing cylinderv 10 of the usual construction, mounted in .bearings `in the frames 11, the cylinder hav-'ing a bed 12 extending partially around the cylinder.

The. printing plate 13 is wrapped around the bed'l2 and heldin place by a series of clamps along each edge of the plate. The form of clamp which I have adopted for purposes of illustration has a body portion 14 with a fixed jaw 15` and `a movable jaw `4 18, so that the edge ofthe plate may be clamped between the jaws 15 and 16. Each clamp is separately pivoted in bearings in Y 16 pivoted at 17` and controlled. by the screws the end of the cylinder or in the block 20,

the latter being held'to the cylinder by thebolt y21. A screw 19 is threaded 'intol'the body Vmember 14" and` exerts a pressure against the edge of the bed 12, so that when the screw 19' is turned, the clamp is moved away from the bedto stretch the plate. The arrangement soifar described is the usual .one and no further. detailed description will be necessary for an understandingl of it; Y i

If, forany reason, it isdesiredr to stretch the platelaterallyalongone or bothof its edges, so as tor-bring the design into proper register with previously printed forms, the arrangementwhich Iprovide will permit this to be accomplished. To this' end, I

mount theclamps in their respectivebearings so that some end motion of the clamp lis permitted, and in the form illustrated, the

clamp is moved endwise .by means of a screw y i 23 threaded into an lear 22 forming part of the bearing '20, the screw 23 pressing against one end of the clamp. While, for some purposes, ity might be Vdesirable to provide means for moving each of the clamps along an edge, I have found fit. to be suicient to provide moving means for the end clamps only,`as illustrated in Fig. 1. Thefscrews v23 arel arranged sothat each end clamp may be moved away from the center of the plate,

so that the same may be stretched to the .amount desired.

Since the endwise motion to the A clamp will be given while vthe sheet is under tension, or, in other` words, while the screw v19 is pressing the front ofthe bed-12, I have found .it desirable to provide some means by which the clamp can be moved endwise while the screw with a heavy pressure against 19 is exerting i-tspressure. To this end, I l

being held in place by screws 25-25 passing through vslots in the plate 24. The plate 24 .is held yieldingly in its normal position by a spring 26 positioned between theplate and a puppetv 27 attached to the bed 12. In a suitable opening in the plate 24 are Aplaced anti-friction devices, which, in the form illustrated, comprisca pair olf .rollers 28 l the ends of which are heldin members 31 forming cages for the rollers, these cagesy being held in normal position by a spring 29 taehed tothe plate 24.

lVith thearrangernent shown, it will be obvious th-at'theclamp may be moved@ bodily cndwise evenl when under very great 'stretching pressure from` the screw 19, because this pressure is carried by the rollers 28, `which will turn as the plateis moved sid'evvise..

' While li have illustratedmy invention in connectionwith a cylinder, it willi be obvious that it may: be used on any form. of printing bed and that the particular embediment of my invention may be varied. within wide limitswithout departing from its spirit.

, fWhat'll claim` and: desire tosecure Abyy tens Patent: of the United Sta/tes is:

1i. A sheet-supporting bed, Adevicesior holding affiexible sheet thereon, comprising a plurality of separate clamps vpositioned alongA oneo. thej edges ofI the' sheet and adapted? to grip said edge, and positively actuated means whereby one1 of? said? clamps may-bemovedf` longitudinally of said edge and* independently of the remaining'clamps,

' and? While the clamp being moved is' under strainto hold the sheet' on said bed.

2. A sheetsupporting bed, devices for holding a fl'eXiblesheet thereon, comprising 'a plurality of separate clamps positioned alongopposite edges of the sheet andy adaptvedv tor grip said edges, andipositivelyfactuated' means w-hereby-'oneof said 'clamps may bei moved longitmdinally of? theI edge with 'which itffengages and independently ofl the remaining clamps, and.- Whi ler` the clamp beingi movedf is under strainito the sheet "iflampsf--m'ay` be moved'in 'opposite directions longitudinallyoff said edge independently 'off thefiemainingclamps, andt While the 'clamps vbeing meyedfare underv strain to hold the-sheet 'on'\said-Shed.i

4e "A sliee'ttsupporting hed, devices l f'or bed while said screw ated means whereby at least two of' said clamps on each edge may be moved in opposite directions longitudinally of said edges independently of the remaining clamps, 'and while the clamps being moved are Vunder l, strain to hold the sheet on said'bed V5. A sheet supporting bed, devices for holding a flexible sheet thereon, comprising a clamp adapted to grip the edge'of the sheet, pressure devices .adapted to exert pressure against the bed to move Vthe clampto Vstretch the sheet on the bed, and` positively actuated means whereby one of said clamps may be moved longitudinallyI of said: edge independently oli they remaining clamps and while the clamp being movedis under strain to hold. the sheet on said bed.

6. sheet supporting bedr, devices for holding aflexible sheet thereon, comprising a clamp adapted to. grip the edge of the sheet,-pressure devices adapted toeXert pres# sure against the bed to moire the clampI to stretch the sheet on the bed, anti-friction devices between the bed and said pressure devices, `and means wherebyfthe clampJ may be moved-alongl the edge of the bed; while said press-ure: devices, are holding theY sheet stretched. Y Y

7. A sheet supporting bed, devices.A for holding a flexible sheet thereon,l comprising al clamp adapted to grip the edgev of the sheet, pressure devices adapted be. exertpres sure against they bed to move the clamp. to stretch the sheet onv the-bed, anti"-iricti'onfl de:- vices comprisinga movable plate and-1 rollers betweenk the bed and said pressure devices, and means whereby the clamp may be movedf along lche edge of thebe'd while said pressure devices are holding the sheet stretched. Y V A V 8: A sheet'y supporting' bed, devices for holding a flexible sheet. thereon, compnising ay clamp adapted togrip the edge oliV the sheet, a screw: adapted-toexert pressure against the edge of the bed to movezthe clamp to stretchthesheet onv the'bed, xa niember contacting withthe endiiof the-,screw and mov-able longitudinally? of the.- edge off the plate, rollers between said?v plate andthe edge of? the bed, and meansrwherebyl the clamp mayjbe moved alongfthee'dgeir-ofr the is holding theysheet stretched;

9. A sheet supporti-ng; bed, devices` for holding a flexible sheet thereon, Vcomprising a clampadaptedV vto grip theedge of the sheet, a screw vadapted to 1 eXert pressure against the edge of' the bed to: move1- the lclamp to stretchthe sheet on therbed, plate mountedl ony the ledge 1 ofiV the bed and"V movable longitudinally thereof f andi adapted. to

Contact With the end'of the screw, anti-lriction` 'bearings betWeenLsaid-plate; and.' said bed', and meansifwherebyst'he clamp Ymay Abe lplate longitudinally' thereof and to hold the plate in its stretched position.

11. A sheet supporting bed, devices for holding a flexible sheet thereon, comprising a plurality of separate clamps positioned along opposite edges of the sheet and adapted to grip said edges, and means to move said clamps to stretch the edges of the plate longitudinally thereof and to hold the plate in its stretched positiom 12. A sheet supporting bed, ldevices for holding a flexible sheet thereon, comprising a pluralityl of separateV clampspositionedl along onevof vthe edges of the sheet and adapted to grip said edge, and positively actuated means to move one of said clamps longitudinally of said edge independently of the remaining clamps and to hold the clamp in adjusted position.

13. A sheet supporting bed, devices for holding a flexible sheet thereon, comprising a plurality of separate clamps positioned along opposite edges of the sheet and adapted to grip said edges, and positively actuated means tomove one of said clamps on each edge longitudinally of said edge independently of the remaining clamps on that edge and to hold the clamp in adjusted position.

l14. A sheet'supportin bed, devices for holding a fiexible sheet t ereon, comprising Va Vplurality of separate clamps positioned along one of the vedges of the sheet and adapted to grip said edge, and positively actuated means to move at leasttwo of said clamps in opposite directions longitudinally ofsaid edge and to hold the clamps'in adjusted position.

. 1,5. A sheet supportin bed, devices for holding a flexible sheet t ereon, comprising a plurality of separate clamps positioned along opposite edges of thesheet and adapted togrip said edges, and positivel actuated means to move at least two o said clamps on each edge in opposite directions longitudinally of said edge and to hold the clamps in adjusted position.

' JOSEPH WHITE. 

